[Macca05]

Hello everyone,
I have been a long time lurker on this site. I finally took the plunge and tried to build myself a cnc machine. It is build from MDF and when I first built it I used threaded rod. This made the machine very slow but really accurate. I upgraded it to 1605 antibacklash screws and was able to increase my speed quite a lot although I only cut around 1200mm/min.
I am now having major problems cutting circles and squares


In both photos the top circle and square are inner cuts and the bottom circle and square are outer cuts. Im using Vcarve desktop.
I thought it was to do with the Motor settings and I adjusted them slightly but as you can see the inner cuts worked alot better but the outer cuts got larger.
I have checked in vcarve and there does not seem to be a final pass or anything of the sort so Im assuming that since adding the new screws and the speed difference i am now getting deflection or backlash
Can someone please point me in the right direction. I can add photos of my machine if needed too
There are smaller squares and circles in there too but they were terrible

Thanks for your help
Macca

[louieatienza]

Check the screw for any axial play, make sure your fixed end bearing is mounted properly, the screw bearing journal is properly seated and spacer, and no backlash with your motor couplers. Also realize C7 ballscrew lead error us .002" and likely the axial play at the nut the same. I know advertised as anti-backlash but that does NOT mean zero backlash.

[Macca05]

Ok thanks i will check that today. I know my y axis is not mounted properly. Atm i cant change the mounts as im not able to cut anything with this error.

Are the pictures showing up. This is my first post here and i dont seem to be able to see the pictures.

If the error is .002 i think that equals .05mm. At the moment my error is around 2mm

Thank you
Macca